A variety of antineoplastic agents are presently in use in chemotherapy. See generally Cuttings Handbook of Pharmacology, 7th Ed., Chapter 13, Scaky and Barnes. However, because of their often complex structure, antineoplastic agents are known to exhibit low stability in the bloodstream. Often, chemotherapeutic agents are extremely insoluble, and are thus poorly transported across cell membranes. Additionally, the effective amount of antineoplastic agents can be greatly reduced through binding of such agents with plasmoproteins, as well as other non-specific interactions in the bloodstream occurring prior to the agents reaching the target. Multidrug resistance (MDR) is a further complication observed with such chemotherapeutic agents, resulting in host resistance to structurally different antineoplastic agents.
Certain antineoplastic agents currently in use have demonstrated toxicity in patients. It is thus desirable to either {i} decrease toxicity of these compositions, {ii} increase their overall anti-cancer activity, or {iii} both. It is similarly desirable to overcome MDR in patients receiving chemotherapeutic agents.